An amplifier, such as an audio amplifier used to control the level of audio signals, typically includes a current fault detection mechanism. A current fault detection mechanism detects short circuits at an amplifier output (e.g., a short circuit between an amplifier output and ground). Upon detecting such a condition, the current fault detection mechanism or other associated circuitry shuts down the amplifier or the device in which the amplifier resides to protect the amplifier and/or the device from overheating and damage associated with the current fault state.
While a current fault detector is useful in detecting an output short circuit, current fault detectors do not assist in detecting amplifier output loads that are not desirable, but that are not short circuits. For example, current fault detectors are unable to detect loads that are lower or higher impedance than is desirable for good amplifier performance.